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17ct Amethyst (Cabochon, 20.19×13.46mm, Violet) vs 17ct Alexandrite (Cabochon, 18.02×12.01mm, Bluish Green)


Quick summary: When looked from above (face-up position), 17ct Amethyst (20.19×13.46mm, cabochon cut) appears 26% larger than 17ct Alexandrite (18.02×12.01mm, cabochon cut). See below how they compare side-by-side on a ring and finger.

17ct Amethyst (cabochon cut)
vs
 17ct Alexandrite (cabochon cut)
violet
 
bluish green
20.19×13.46 mm 18.02×12.01 mm
actual size
Actual size of 17ct Amethyst (cabochon cut, 20.19×13.46mm, Violet color)   Actual size of 17ct Alexandrite (cabochon cut, 18.02×12.01mm, Bluish Green color)
 
Actual size is set for screen
Ring: Skin tone:
Ring width: 3.0 mm
Left finger image
Ring on left finger
Violet 17ct Amethyst (cabochon cut, 20.19×13.46mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
Bluish Green 17ct Alexandrite (cabochon cut, 18.02×12.01mm) on a right ring and finger
Your settings
Ring
 Gold
Skin tone
 Light
Ring diameter
 16.9 mm
Ring width
 3.0 mm
Finger length
 64 mm
Finger coverage
 80% vs 72%
Saved...
Ring diameter: 16.9 mm
USA UK Asia EU1 EU2
Actual sizes of 17ct Amethyst Cabochon (20.19×13.46mm, Violet) and 17ct Alexandrite Cabochon (18.02×12.01mm, Bluish Green) as they would appear on a ring and finger. Adjust the ring and finger size to get an idea of how these gemstones would look on your finger.

Where to buy?

For certified gemstones, high-end gemstone jewelry, and birthstone jewelry, see Blue Nile

Face-up Size

All things being equal, Alexandrite will face-up smaller than Amethyst for a given carat weight, because it has higher specific gravity (3.73 vs. 2.65 - this means it's "heavier" compared to Amethyst of the same size). Face-up size also depends heavily on the proportions of the cut.

Face-up area is a measure of the size of the gem when viewed from above (as set in a ring). It tells you how big the gem is at the girdle plane.


17 Ct Amethyst (Cabochon) 17 Ct Alexandrite (Cabochon)
20.19×13.46 mm vs 18.02×12.01 mm
222.84 mm²   177.46 mm²
Face-up size outline for 17ct Amethyst (20.19×13.46mm, cabochon cut)
Face-up size outline for 17ct Alexandrite (18.02×12.01mm, cabochon cut)
17ct Amethyst Cabochon (20.19×13.46mm)
17ct Alexandrite Cabochon (18.02×12.01mm)
Difference: 26% (45.38 mm²)
17ct Amethyst (Cabochon, 20.19×13.46mm) has approx. 26% more face-up area than 17ct Alexandrite (Cabochon, 18.02×12.01mm).


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